Devices such as automobile radios or personal computers contain subassemblies such as cassette playing mechanisms or disk drives that are attached to the chassis using threaded fasteners. The chassis provides structural support for the subassemblies and also provides electromagnetic shielding to limit electromagnetic interference (EMI) experienced by, and/or created by the device. The fasteners ensure that each subassembly within the chassis is properly located and securely retained within the chassis.
The use of such fasteners can have numerous drawbacks, particularly in a high volume production setting. The process for applying or installing fasteners can vary, but there is usually some degree of automation required, ranging from manually loading a screw into a bit on a pneumatic driver to using self-feeding automated machines. Typically, the torque applied by the device used to drive the fasteners must be monitored regularly and adjusted in order to assure proper seating of the fasteners. When fasteners are used, sheet metal tolerances, as well as tolerances of the fasteners themselves, have to be maintained at tight levels to allow for the minimization of stress in the assembly when aligning multiple fasteners with corresponding holes in the chassis and in the subassembly.
When threaded fasteners are used to assemble an electrical device, the assembly cycle time can be very long especially in high volume production. An operator assembling the device must typically first obtain the threaded fastener, orient and position it in alignment with the driver bit, then manipulate or actuate the machine to drive the threaded fastener. Furthermore, using threaded fasteners presents a risk of any one of the following upstream failures occurring: stripping of fastener threads; insufficient torque resulting in an unseated fastener; excessive torque resulting in distension/deformation of the fastener or adjacent electrical components; installation of the wrong fastener type or size; foreign object damage due to fasteners and/or metal shavings dropping onto the assembly and/or subassembly; and stripping of the head of the threaded fastener. Also, a fastener installation tool such as a driver and bit can slip off the fastener and impact an electrical component resulting in a damaged assembly.
If self-tapping fasteners are used, the process of driving the self-tapping fasteners into sheet metal often causes shavings of sheet metal to disperse into the assembly. Such shavings have been known to cause electrical failures, such as shorts or corruption of magnetic components that can permanently damage the product. If self-tapping fasteners are not used, an extra production step is required to pre-form threads in the sheet metal of the chassis and/or the subassembly to be installed within the chassis.
Fasteners further require an additional inventory burden on the production line in that the production line must be continuously stocked with part numbers (fasteners) other than the integral components that add value to the assembly. Also special tools specifically required for assembly, using fasteners, such as drivers and bits, must be continuously monitored and maintained for proper performance, wear and torque specifications. Typically, the top and/or bottom surface of the chassis must be secured in place after the subassembly is attached to the chassis.
Special fixtures are often required on the production line to secure a subassembly in a proper location and orientation while it is mounted within the chassis with fasteners. Such fixtures can be very complex, and the use of such fixtures usually requires extra handling of both the subassembly and of the resulting assembly thereby adding to the production cycle time and potentially compromising quality of the final product.
FIG. 1 illustrates the construction of a typical prior art automotive radio/compact disc (CD) player 10. Radio/CD player 10 comprises a radio subassembly whose principle circuit components are carried on a circuit board 12 and a CD player subassembly 14. The circuit board 12 and the CD player 14 are encased within a common chassis 16 made up of sheet metal components. Chassis 16 includes a wraparound housing 18 defining a back and sidewalls, a top cover 20, a bottom cover 22 and a front plate 24 which are interconnected by numerous threaded fasteners to collectively enclose the subassemblies. The top and bottom covers 20 and 22, respectively, are provided with large arrays holes or openings for airflow and ventilation of heat generated within the radio/CD player 10. A convector or heat sink 26 is carried on an outer surface of one of the chassis sidewalls and is interconnected through a port/window 28 to a power device assembly 30. A trim plate assembly 32, along with a support pad 34 and CD dust cover 36 are affixed to the front plate 24, providing an operator control interface with the radio/CD player 10. Circuit board 12 is electrically in-circuit with the CD player subassembly 14 through an intermediate flex wire cable 38 and with the power device assembly 30 through a jumper cable 40. Information bearing labels 42 and 44 are provided for future reference by the operator and service technicians. The radio/CD player 10 is electrically interconnected with an antenna, power supply, speakers and other related systems of a host vehicle by rear-facing connectors 46 carried on the circuit board 12 which are registered with openings 48 in the rear wall of wraparound housing 18. The radio/CD player 10 is mounted within a host vehicle by threaded fasteners passing through openings in mounting features 50 extending from front plate 24 and a rearwardly directed mounting bushing 52 which is threadably affixed to a stud 54 carried on the outer surface of the rear wall 56 of wraparound housing 18. As best seen in FIGS. 11 and 12, the shank of the stud 54 extends outwardly through a hole 58 disposed concentrically with a localized recess 60 and the stud 54 is seated within the recess 60. FIG. 90 illustrates another known stud design including a threaded shank secured to the rear wall 53 of a radio set 51 by a set nut 55 and receiving a molded rubber, plastic or vinyl stud 57 thereover. Note the large number of threaded fasteners 59.
The radio/CD player 10 of FIG. 1 is of ordinary complexity and may require fifty or more threaded fasteners to complete the manufacturing process. Installation of that many fasteners may require that the in-process chassis be re-positioned/re-fixtured ten to fifteen times as it passes along an assembly line of eight to ten skilled workers/work stations.
Vehicle entertainment systems usually include an audio component such as a radio to enable receiving signals from antennas, contain various forms of playback mechanisms, and have the capacity to accept data from user devices like MP3 players. Typically, the radio has a decorative assembly that provides man-machine interface as well as displaying pertinent data relative to the selected media and audio settings. Also, the back-end or chassis is constructed of metal to provide various functions to ensure the performance of the radio in the vehicular environment. The structure to contain the mass from playbacks, the heat conductive properties, and the electrical shielding and grounding are just a few of the advantages to using the metal construction. Unfortunately, with the density of the metal, the disadvantage of added weight is a side effect of the typical construction. In a vehicle, added weight impacts fuel economy, as well as other hidden costs during assembly that can effect the cost of the product, like sharp edges of metal can be a potential hazard for assemblers in the manufacturing plant as well as added weight can limit the packaging of multiple parts in containers for inter and outer plant distribution.
Thermal Management System
Devices such as automobile stereos, audio amplifiers, home stereo systems, two-way radios, computers, signal conditioners/amplifiers, compact disc playing mechanisms, and cassette tape playing mechanisms are examples of products that typically require electrical components to amplify signals and regulate power. Accordingly, such devices typically contain numerous electrical components such as single in-line package (SIP) amplifiers and regulators that are typically soldered into printed circuit boards. Such electrical components generate heat in use. The heat must be dissipated away from the electrical components to avoid damage that can be caused by excessive temperatures in the electrical components. For example, excessive temperatures can cause delicate electrical leads to fail or insulating materials to melt, thereby causing a short circuit resulting in damage to, or even failure of, the entire electrical device.
A convector is often mounted to an outer surface of such a device to dissipate heat generated by components by transferring the heat away from the components and the device to the convector and then to the air through radiation. In order to accomplish this, it is preferable that the convector be physically in contact with the component. The components and the convector can be pressed together to allow even better heat conduction from the components to the convector. Sometimes an intermediary material such as a thermal pad or silicon grease is used between the component and the convector to assist in creating an adequate heat transfer junction.
Many convectors are made from aluminum due to the high heat conductivity of that material. Convectors often include a plurality of fins to increase the effective surface area of the convector and thereby increase the rate at which the convector can dissipate heat. Typically, aluminum, convectors are formed by an extruding process, during which the fins can also be formed integrally therewith.
Convectors are usually assembled to the component or components during final assembly of the overall device in which they are used. At final assembly, components such as SIP amplifiers are already soldered into a printed circuit board. The order of assembly can vary as to which component is assembled into the chassis first. The printed circuit board can be installed into the chassis before the convector is mounted to the printed circuit board and the chassis. Alternatively, the convector can be mounted to the chassis before the printed circuit board is mounted to the convector. Sometimes, the convector is assembled to the printed circuit board to form a subassembly before being assembled to the chassis.
Typically, components are attached to the convector using a clip and one or more threaded fasteners that extend through a hole in the clip and into a hole in the convector. The clip, component and convector must all be simultaneously held in a fixture and then be fastened together with a threaded fastener. If the component includes a hole to accept a threaded fastener, it can be mounted directly to the convector using a threaded fastener that extends through that hole, without using a clip.
The use of such fasteners can have numerous drawbacks, particularly in a high volume production setting. Often, each hole in the convector that receives a fastener must be separately drilled or punched. This is especially true for an extruded convector if the axis of the hole is not aligned with the direction in which the convector is extruded. The fastening process can vary, but there is usually some degree of automation required, ranging from manually loading a screw into a bit on a pneumatically or electrically powered driver to using self-feeding screw machines. Typically, the torque applied by the device must be monitored regularly and adjusted in order to assure proper seating of the fasteners.
The clamping force between the convector and the component should be at a proper level to ensure sufficient heat transfer to the convector. When fasteners are used to attach the convector to the component, clamping force is a function of the type of fastener and its condition and degree of assembly (e.g. the level of torque applied during installation of the fastener). Thus, a threaded fastener that is not seated all the way will give less clamping force than one that is seated all the way. Or, a stripped or improper type of fastener may provide an insufficient clamping force.
Special fixturing is often required to hold a component in the proper location while it is mounted to the convector using one or more fasteners. Such fixturing can be very complex and use of such fixturing usually requires extra handling of both the component and of the resulting assembly, thereby adding to the production cycle time and potentially compromising quality of the final product.
When threaded fasteners are used, the assembly cycle time can be very long, especially in high volume production. The operator must specifically obtain the threaded fastener, bring it in contact with the driver bit, then drive the threaded fastened. If self-tapping fasteners are used, the process of driving the self-tapping fasteners into metal often causes metal shavings to disperse into the assembly. Such shavings have been known to cause electrical failures that can permanently damage the product. If self-tapping fasteners are not used, an extra production step is necessary to form threads in the metal of the convector.
Accordingly, there is a need for electrical assemblies that do not require fasteners or tooling for securing a component to a convector.
Electrostatic Discharge Device
Static electricity (electrostatics) is created when two objects having unbalanced charges touch one another, causing the unbalanced charge to transfer between the two objects. This phenomenon commonly occurs in homes, vehicles and other environments when the air is dry (i.e. has a characteristic relatively low level of humidity). For instance, when a person slides onto a car seat, electrons may transfer between the two, causing the surface of the person's body to store a charge. When the person, then, touches a vehicle component, the charge may travel (discharge) from the body to the component, thus creating static electricity. If the object touched is an electronic device, such as a home stereo, home theatre system, computer, vehicle entertainment system or other electronic media system, this electrostatic discharge can be harmful to the sensitive electronic components of the device. For instance, when a person slides onto a vehicle seat and inserts a disc into the car stereo, a charge may travel from the body through the disc to the sensitive electronic components in the vehicle stereo. Similar problems may occur when using DVD and other magnetic media and disc players.
Accordingly, problems with the drainage of a static electric charge impacting sensitive electronic components continue to persist.
Living Hinge Button Switch Linkage
A variety of automotive accessories, e.g., an automotive radio, within a motor vehicle employ button switches. Traditionally, buttons for the button switches have been fabricated and decorated (i.e., painted and laser trimmed) individually. The buttons are then set in a separate housing that includes a plurality of integrally formed guides for accepting the buttons. Unfortunately, each of the buttons has required individual fabrication and decoration, which significantly increases the total cost of an end product so designed. Further, as the individual buttons are actuated, they can produce a squeaking noise due to the fact that each of the individual buttons includes a number of posts that mate with integrally formed guides in the housing. Various automotive accessories, such as an automotive radio, also receive inputs from rocker switches, which, similar to button switches, have been painted and laser trimmed and also may create noise when a user actuates the rocker switch as the switch may engage a separate housing or trim plate. Additionally, both button and rocker switches have generally required additional components (e.g., springs) to provide a desired tactile feel.
Thus, what is needed is a parallel guide mechanism for a switch that provides noiseless actuation and guided movement and allows for material and/or component design that provides a desired actuation tactile feel without increased component cost.
Integrated Vehicle Display Lighting Assembly
Vehicle display assemblies often use a backlit liquid crystal display (LCD) so that the display can be viewed easily by the user. Fluorescent light is the most common backlight source for LCDs. To ensure that the display can be read in daytime ambient light, the display backlighting is relatively intense.
The display assemblies may also include buttons for operating, for example, a radio or a CD player. Current assemblies illuminate each button with its own incandescent light source, providing backlighting and color for any graphics on the button. Each light source may include a colored boot to produce a desired light color for the button graphics.
As vehicles incorporate more features that require more buttons, the number of light sources also increases. The heat generated from the incandescent lights, however, elevates the temperature of the buttons by as much as 20° C., enough to be noticeable by a user. Further, the increased temperature may place undesirable thermal stress on the display components. Thermal protection algorithms may be used to monitor the assembly temperature and reduce the light intensity if the temperature reaches a selected threshold until the temperature drops to an acceptable level. Unfortunately, these systems require additional, cumbersome circuitry for turning the button light sources on and off.
There is a need for a display assembly lighting system that can illuminate a main display and adjacent buttons while keeping the assembly temperature within a desirable range.
It is known in the art that illuminated display systems, such as those found in radio receivers, compact discs, and heating, ventilation, and air conditioning (HVAC) controllers, include a back-lit display panel. Typically, it has been common practice to locate light pipes between a printed circuit board and the display panel to direct light from a light source to a portion of the display panel for controlled illumination. However, because this location of the light pipe is typically shared by other electrical components and mechanical structures (i.e. button bodies, potentiometers, plastic ribs, LCD displays, etc.), the design of the light pipe may become complex, which may affect the efficiency of the lighting system.
Accordingly, a final design of the light pipe has often included complex structures that weave between the electrical components and mechanical structure. Once light is provided to an entrance port of the light pipe, gradual changes in direction of light propagation by means of total internal reflection on non-parallel light pipe walls tend to introduce losses as collimation decreases. Losses in collimation also increase the difficulty in directing light exiting the light pipe to the specific areas of the display panel.
The complexity of such light pipe designs makes computer simulation difficult and time consuming, which lends to prevention of design optimization by means of iterative prototyping and expensive design cycles drawn out with proof of concept often being delayed until injection molded light pipe prototypes can be produced. As such, a need exists for improving the collimation effects and efficiency of light pipes applied in an illuminated display system.
Self-Aligned Button Retainer
There are numerous types of switch mechanisms in use today for operating and regulating systems and components of vehicles and other devices. The switch mechanisms can be on-off type switches, switch mechanisms which regulate the volume, amplitude and/or intensity of various systems, switch mechanisms which are available only for emergency-type usage, and the like.
In automobiles and other vehicles, there are numerous types of switch mechanisms which are used for the various electronic components and systems that are available and in use in the vehicles. These electronic components include windshield wipers, emergency lights, turn signals, cruise control, power seats, power windows, heated seats, four-wheel drive systems, overdrive systems, navigation systems, timing systems, clocks, mileage, trip or travel systems, and the like. Many of these mechanisms have dual functions, such as being used not only to control, for example, the on-off status of the component or system, but also to adjust one of its functions, such as amplitude, balance, base, treble, etc. Many such switches utilize rocker-type buttons which pivot or rotate around a central point or section and have two ends which are adapted to operate or actuate certain switches or systems. Automotive entertainment systems such as radios and CD players frequently use push button type switches in space-saving compact arrays, with packaging space being a premium.
Switch mechanisms are typically designed to meet various criteria and considerations other than function. The considerations include appearance, aesthetics, ease of assembly, positioning, ease of use, versatility of function, and design. These considerations can affect the size, color, type, and method of activation of the switch mechanism. The switch mechanisms are also made from various types of materials, including plastic, acrylic, and metal materials. In this regard, cost and durability factors can be significant in the final selection of the switch mechanisms to be utilized.
Although there are numerous switch mechanisms in use today which operate satisfactorily, there is a constant need to improve the operation, versatility and appearance of various switches, as well as to correct problems with existing switches. For example some of the switch mechanisms provide excess freedom of movement, have undesirable noise problems, are too expensive, have alignment problems in the socket or housing in which they are positioned, do not operate with the requisite tactile “feel”, or are simply too difficult to operate for the desired function. Thus, a need exists for improved switch mechanisms, particularly those which minimize noise problems, have improved alignment, have the desired “feel” or can be adjusted to achieve the desired feel, and which can be easily and simply actuated.
Interface with Personal Entertainment Devices
Vehicle entertainment systems usually include an audio component such as a radio to enable receiving signals from antennas, contain various forms of playback mechanisms, and have the capability to accept data from user devices such as MP3 players. Typically, the radio has a decorative assembly that provides man-machine interface as well as displaying pertinent data relative to the selected media and audio settings.
Many consumer electronic devices like the popular iPod from MacIntosh have become mainstream must-haves for certain demographic groups of consumers. Automobile manufacturers are developing methods to allow the consumer to connect to the automobile's entertainment system with their personal music device, whether it be an iPod, a memory stick via a USB port, or a similar device. Several automobile manufacturers such as BMW and VW/Audi have provided a pig-tail or wired connection for an iPod in their glove box.
Referring to FIG. 127, alternative prior art approaches are illustrated wherein a personal device is directly interconnected with the vehicle entertainment system through a cable and phone jack plugged into an auxiliary (aux) input in the front face of the entertainment system, or, alternatively, plugged into a pig-tail connector located in the vehicle glove compartment.
This arrangement enables the consumer to connect the vehicle audio system with their personal device. Some automobile radios have an auxiliary jack on the front of the radio. The auxiliary jack allows playing the music, but does not necessarily allow for player control through the radio. This requires the device be accessible for control of the music.
The problems with the glove box approach are the potential for damage to the device from other contents in the glove box, and the cable connection offers no flexibility for connecting to another device. Damage may occur to the cable as well through normal use.
The auxiliary jack method allows more flexibility for devices, but limits the control and may incur damage through impact while a plug is connected.
Some aftermarket radios offer a USB (Universal Serial Buss) port on the front panel thereof, but may also incur damage due to the potential leverage on the face of the unit when a flash memory is connected, not to mention vehicle occupant impact issues resulting from braking and collisions. Furthermore, connection interfaces open to the vehicle passenger compartment environment risk system damage from foreign objects and air-borne contamination, not to mention being aesthetically unattractive.
With most automotive suppliers, the present generation of radios are typically designed to fit a standard frontal area size. Typically, the DIN standard (issued by the Deutsches Institut für Normung, or German Institute for Standardization) is used for either a “2DIN” or a single “DIN” size in most radios. 2DIN radios typically have larger displays and contain multiple disc changers integrated into the package.
With the advent of music storage devices, like flash memory and devices like the iPod™, there is less dependency on multiple disc changers and more desirability for the radio to communicate with the personal music storage or music device carried by the consumer. The rapidly changing customer market has initiated a drive to feature content on OEM (original equipment manufacturer) supplied radios for automobiles to provide those wants and that has an impact on interchangability and potential safety issues.